Generally, a stabilizer control device for a vehicle is used to stabilize the vehicle, while the vehicle is turning, by applying an appropriate roll moment to the vehicle by use of an actuation of the stabilizer bar in order to reduce or prevent a rolling on the vehicle. For example, a known rotary actuator disclosed in JP2775242B2 (corresponding to U.S. Pat. No. 5,700,027A) controls a stabilizer by which torsion bar halves are connected each other, and such rotary actuator is driven by hydraulic fluid under pressure. Further, a roll stabilization of a vehicle disclosed in JP2002-518245A (corresponding to U.S. Pat. No. 6,425,585B1) includes an electromechanical slewing actuator arranged between stabilizer halves. Specifically, a motor and a speed reducing gear device are provided between stabilizer halves. Further more, another type of stabilizer disclosed in JP2003-519588A (corresponding to U.S. 2002-180167A1) includes stabilizer halves formed by bending, and an actuator. The actuator is comprised of an electric motor and a speed reducing gear mechanism and mounted between the stabilizer halves.
The speed reducing gear mechanism includes a general multistage planetary gear mechanism. Specifically, a paradoxical planetary gear mechanism is known as a speed reducing mechanism, which can obtain a large reduction ratio.
Such planetary gear mechanism is described in a document Mechanism, Kiyoshi Ogawa and Isao Kato, Morikita Shuppan Co., Ltd., Published Mar. 1, 1976, 1st edition, 7th printing, 164-165 (hereinbelow referred to as Document 1). In Document 1, the planetary gear mechanism includes a pair of internal sun gears (a static sun gear and a rotational sun gear), and one of the sun gears meshes with planetary gears, and the other of the sun gears also meshes with the same planetary gears. Further, another speed reducing mechanism, by which a greater reduction ratio can be obtained, is described as Harmonic Drive® (registered by Harmonic Drive Systems, Inc) in a document Principles of the Harmonic Drive mechanism, retrieved from the Internet: URL: http://www.hds.co.jp/principle (hereinbelow referred to as Document 2).
The actuators disclosed in JP2002-518245A (corresponding to U.S. Pat. No. 6,425,585B1) and JP2003-519588A (corresponding to U.S. 2002-180167A1) are actuated by electric motors, on the other hand, the rotary actuator disclosed in JP2775242B2 (corresponding to U.S. Pat. No. 5,700,027A) is actuated by the hydraulic pressure. According to such rotary actuator, the torsion bar is connected to a rotor shaft of the rotary actuator by means of a spline-fitting. The spline-fitting can be used for another actuator having another structure, however, in any case, it is important that the stabilizer halves are connected to the actuator so as not to generate noise caused by a rattling therebetween while each stabilizer halves rotate relatively. Thus, it is fundamental that the stabilizer halves are spline-fit to the actuator by press fitting.
Furthermore, in the same manner as the stabilizer halves disclosed in U.S. 2002-180167A1 that are bent so as to be in a complex form, the stabilize bar is generally bent so as to be in a complex form. Thus, it is difficult to spline-fit such stabilizer bar by press fitting to a member of the actuator. For example, because the stabilizer bar doesn't include a flat portion, which is used for the spline-fitting with press fitting, and because it is difficult to form such flat portion on the bent stabilizer bar for receiving a large load which is applied to the stabilizer while press-fitting, it becomes difficult to spline-fit the stabilizer bar by press-fitting to the member of the actuator. Furthermore, even when the stabilizer bar is press-fit in the spline hole in a manner where the stabilizer bar is hold by means of a clamp, the stabilizer bar may slip on the clamp, as a result, it becomes difficult that a required press-fitting load is secured. Thus, an additional device, such as a particular press-fitting device may be required to use.
Thus, a need exist to provide a stabilizer control device by which at least either one of a pair of the stabilizer bars can be easy and firmly spline-fit to a component of an actuator, which is used for controlling a torsion force of the stabilizer bar.